diff options
Diffstat (limited to 'src/main/java/org/traccar/helper/DistanceCalculator.java')
-rw-r--r-- | src/main/java/org/traccar/helper/DistanceCalculator.java | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/src/main/java/org/traccar/helper/DistanceCalculator.java b/src/main/java/org/traccar/helper/DistanceCalculator.java new file mode 100644 index 000000000..88d4ef8a4 --- /dev/null +++ b/src/main/java/org/traccar/helper/DistanceCalculator.java @@ -0,0 +1,53 @@ +/* + * Copyright 2014 - 2016 Anton Tananaev (anton@traccar.org) + * Copyright 2016 Andrey Kunitsyn (andrey@traccar.org) + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.traccar.helper; + +public final class DistanceCalculator { + + private DistanceCalculator() { + } + + private static final double EQUATORIAL_EARTH_RADIUS = 6378.1370; + private static final double DEG_TO_RAD = Math.PI / 180; + + public static double distance(double lat1, double lon1, double lat2, double lon2) { + double dlong = (lon2 - lon1) * DEG_TO_RAD; + double dlat = (lat2 - lat1) * DEG_TO_RAD; + double a = Math.pow(Math.sin(dlat / 2), 2) + + Math.cos(lat1 * DEG_TO_RAD) * Math.cos(lat2 * DEG_TO_RAD) * Math.pow(Math.sin(dlong / 2), 2); + double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a)); + double d = EQUATORIAL_EARTH_RADIUS * c; + return d * 1000; + } + + public static double distanceToLine( + double pointLat, double pointLon, double lat1, double lon1, double lat2, double lon2) { + double d0 = distance(pointLat, pointLon, lat1, lon1); + double d1 = distance(lat1, lon1, lat2, lon2); + double d2 = distance(lat2, lon2, pointLat, pointLon); + if (Math.pow(d0, 2) > Math.pow(d1, 2) + Math.pow(d2, 2)) { + return d2; + } + if (Math.pow(d2, 2) > Math.pow(d1, 2) + Math.pow(d0, 2)) { + return d0; + } + double halfP = (d0 + d1 + d2) * 0.5; + double area = Math.sqrt(halfP * (halfP - d0) * (halfP - d1) * (halfP - d2)); + return 2 * area / d1; + } + +} |